Field of the Invention
The present invention relates generally to trailer jacks. More particularly, the present invention relates to improved lever system for assisting the release of plunger pins on trailer jacks such as may be used, for example, on construction trailers, livestock trailers, goose-neck trailers, horse trailers and heavy duty utility trailers.
State of the Art
Trailer jacks are used to lift and/or hold a portion of a trailer at a desired height. The trailer jack may be used, for example, to allow the trailer to be unhitched from a towing vehicle. Likewise, the trailer jack may be used to stabilize the trailer during loading, unloading or other use of the trailer.
Conventional trailer jacks typically include an upper/outer tubing member and a middle/inner tubing member which can be adjusted to telescope in or out of the upper/outer tubing member via a crank or some other structure which allows for fine adjustment of the trailer jack.
Gross adjustment of the trailer jack is provided by a lower/innermost tubing member which slides relative to the middle/inner tubing member. One or both of the middle/inner tubing member and the lower/innermost tubing member typically have a plurality of holes through which a pin can be advanced to hold the lower/innermost tubing member relative to the middle/inner tubing member. Removing the pin from the hole allows the lower/innermost tubing member to slide relative to the middle/inner tubing member, thereby providing gross adjustment.
During travel, the lower/innermost tubing member is typically retracted a substantial amount into the middle/inner tube member and the pin is inserted into the hole. This keeps the lower/innermost tubing member retracted and keeps it from coming into contact with the roadway.
When the jack is needed to support the weight of part of the trailer, the pin is removed from the hole. This allows the lower/innermost tubing member to slide relative to the inner tubing member and into contact with the ground. (Often the lower/innermost tubing member has a foot plate attached thereto which actually rests on the ground and adds lateral stability.) If the innermost tubing member is attached to a biasing member such as a spring, the user will typically press down on the foot plate on the lower/innermost tubing member and counteract the biasing of the spring until the foot plate rests on the ground. The pin is then reinserted through a hole to hold the position of the innermost tubing member relative to the inner tube member. The fine adjust mechanism is then used to extend or retract the middle/inner tubing member relative to the outer-tubing member until the desired height is reached.
Once the trailer jack is no longer needed, the pin is pulled out of the hole to allow the lower/innermost tubing member to retract into the middle/inner tubing member. This may be done by manually lifting the lower/innermost tubing member or by allowing a biasing member, such as a spring, to do so. Once the lower/innermost tubing member is retracted, the pin is again inserted to hold the lower/innermost tubing member in the retracted position.
While jack significantly improve the usability of trailers, they can be awkward to use. The pins which are used to selectively hold the middle/inner tubing member and the lower/innermost tubing member relatively to one another are often spring loaded and can be difficult to pull out for some people. It can also be hard to both slide the pin out and lift up the lower/innermost tubing member. Additionally, the pin is usually located at a fairly low position and may require a person to get on their knees to crawl part way under the trailer in order to actuate the pin. Thus, there is a need for a lever system to facilitate release of the plunger pin in a more comfortable position.